1. Field of the Invention
This invention relates to improved hydrocarbon fuels which control the octane requirement increase (ORI) phenomenon conventionally observed during the initial portion of the operating life of spark ignition internal combustion engines.
2. Description of the Art
The ORI effect exhibited by the internal combustion engines, e.g., spark ignition engines, is well known in the art. This effect may be described as the tendency for an initially new or clean engine to require higher octane quality fuel as operating time accumulates and is coincidental with the formation of carbonaceous deposits in the region of the combustion chamber of the engine. Thus, during the initial operation of a new or clean engine, a gradual increase in octane requirement (OR), i.e., fuel octane number requirement for knock-free operation, is observed with an increasing buildup of carbonaceous deposits in the combustion chamber until a rather stable or equilibrium OR level is reached, which, in turn, seems to correspond to a point in time where the quantity of deposit accumulation on the combustion chamber and valve surfaces no longer increases but remains relatively constant. This so-called "equilibrium value" is usually reached between about 3,000 and 20,000 miles or corresponding hours of operation. The actual equilibrium value of this increase can vary with engine design and even with individual engines of the same design; however, in almost all cases the increase appears to be significant, with ORI values ranging from about 2 to 14 Research Octane Numbers (RON) being commonly observed in modern engines.
It is also known that additives may either prevent or reduce deposit formation or remove or modify formed deposits in the combustion chamber and adjacent surfaces and hence decrease ORI. Such additives are generally known as octane requirement reduction (ORR) additives.
For example, in U.S. Pat. No. 4,264,335 to Bellow et al. the cerous or ceric salt of 2-ethylhexanoate is disclosed as a useful additive for suppressing the ORI of a gasoline fired internal combustion engine. It is noted in this patent that the above salt has no effect on combustion efficiency of a gasoline and does not provide anti-knock properties.
In U.S. Pat. No. 4,357,148 to Graiff there is disclosed an additive for controlling or reversing the ORI of a spark ignition internal combustion engine which comprises a combination of (a) certain oil-soluble aliphatic polyamines and (b) certain low molecular weight polymers and/or copolymers of mono-olefins having up to 6 carbon atoms. See also U.S. Pat. Nos. 4,270,930 to Campbell et al. and 3,960,515 to Honnen for the use of hydrocarbyl poly(oxyalkylene)aminocarbamates and hydrocarbyl amines, respectively, to control or reverse ORI.
U.S. Pat. No. 3,506,416 to Patinkin et al. discloses an additive to inhibit ORI of a spark ignition engine which comprises a gasoline-soluble metal salt of a hydroxamic acid. This additive is disclosed as useful in leaded gasolines. Although iron is within the broad group of metal salts of hydroxamic acid that are disclosed as a suitable additive for suppression of ORI, no data demonstrating its effectiveness are given. In fact, the patentees point out that nickel and cobalt are especially preferred for their additive.
Other references describing additives for inhibiting ORI include U.S. Pat. Nos. 3,144,311 and 3,146,203 which disclose utilization of nitrogen ring compounds in combination with organometallic primary anti-knock agent and a minor amount of an ignition control additive selected from the group consisting of phosphorus and boron compounds. U.S. Pat. No. 3,864,098 to Honnen also discloses the use of nitrogen ring compounds for the same purpose.
In addition to the above, the following patents are directed to the problem of ORI or deposit control in a spark ignition internal combustion engine:
U.S. Pat. No. 3,996,024 to Coon which discloses monocarboxylic acid salts of hydrocarbyl amines, which function as rust inhibitory and dispersant hydrocarbon fuel additives, wherein the hydrocarbyl substituent contains from 30 to about 300 carbon atoms;
U.S. Pat. No. 3,873,277 to Coon which discloses liquid hydrocarbon distillate fuel compositions comprising a hydrocarbonaceous distillate fuel boiling in a gasoline range containing an aliphatic hydrocarbon substituted hydrazine;
U.S. Pat. No. 4,198,306 to Lewis which discloses hydrocarbylpoly(oxyalkylene)aminoesters which are monoesters of a hydrocarbyl-terminated poly(oxyalkylene) alcohol and a monocarboxylic C.sub.2 -C.sub.20 (amino-subsituted)alkanoic acid useful as fuel and lubricating oil additives;
U.S. Pat. No. 4,234,321 to Lilburn which discloses fuel compositions containing a deposit control additive which is produced by reacting a hydrocarbylpoly(oxyalkylene) alcohol with excess phosgene and an excess amount of certain polyamines to create hydrocarbylpoly(oxyalkylene) ureylene carbamates; and
U.S. Pat. No. 4,302,215 to Lewis which discloses hydrocarbyl carbonates useful as deposit control additives in gasoline compositions.
Thus, it is one object of this invention to provide a hydrocarbon fuel containing a novel additive which suppresses the ORI of spark ignited internal combustion engines.
It is another object of the instant invention to reverse the ORI phenomenon in a spark ignition internal combustion engine by introducing a novel additive with the
It is another object of the instant invention to provide a two-step method to reverse the ORI phenomenon in a spark ignition internal combustion engine by separately introducing with the fuel a first additive to solubilize carbonaceous deposits in an internal combustion engine and a second additive to inhibit ORI.
It is another object of the instant invention to provide a lead-free liquid hydrocarbon fuel containing a novel additive for inhibiting the ORI of a clean internal combustion engine.
Other objects are to provide new compositions of matter and to advance the art.
Other objects and advantages of the instant invention will become apparent to those skilled in the art from the following description.